CAREER: Unraveling the Role of Thin Water Films in Controlling Subsurface Transport of Surface-Active Contaminants across Scales

环境中的人造化学物质可以通过土壤流入污染地下水，而地下水对日常生活和国家繁荣至关重要。在地面上，许多这类污染物活跃于固体颗粒表面和空气与水的交界面。由于这种表面活动，大量有毒化学物质会积聚在土壤中空气和水之间的空间中，对重要的地下水造成长期威胁。虽然土壤中的大多数空气-水界面来自土壤颗粒表面的薄水膜，但表面活性污染物与薄水膜如何相互作用仍未得到很好的了解。研究人员将调查控制这些复杂相互作用的过程，以改进科学家用来预测和评估人造化学品（如通常称为PFAS的全氟烷基和多氟烷基物质）污染风险的工具。这项研究的结果将导致更有效的清理策略，以减少PFAS和类似污染物对人类健康的危害。科学家们将利用地下水PFAS污染的研究作为一种资源，与高中教师合作，并为他们提供创新的课程工具和培训，以吸引亚利桑那州的高中生，提高他们对STEM的兴趣，并提高他们的经验和批判性思维技能。该项目的目标是促进对渗透带中表面活性污染物的薄膜介导的保留和传质过程的基本理解，并开发一个跨尺度框架，将这些新信息纳入其中，以改进宏观传输模型。该研究将结合薄膜理论、实验图像表征和多尺度建模方法。区分土壤中薄膜和体积毛细管空气-水界面的方法学方法将潜在地改变水文学家如何概念化渗透带中表面活性污染物的运动。PI将与亚利桑那大学的合作推广亚利桑那水教育项目WET、图森公立学校的STEM教师和教育学院的教授合作。项目教育团队将共同开发、测试并正式制定一个完全基于探究的教育计划，该计划包括建立和使用物理和数字模型的实践经验，以加深理解和解决问题。这个正式的教育项目将通过由图森水务公司和亚利桑那州水资源部支持的亚利桑那项目WET的现有基础设施提供给亚利桑那州的所有高中。该奖项由水文科学和环境工程项目共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，认为值得支持。

Human-made chemicals in the environment can flow through soils to contaminate groundwater that is critical to daily life and the Nation’s prosperity. In the ground, many such contaminants are active at surfaces of solid particles and the interfaces between air and water. Because of this surface-activity, significant amounts of toxic chemicals can accumulate in the spaces between air and water in soils and cause long-term threats to essential groundwater. While most of the air–water interfaces in soils are from thin water films on soil-grain surfaces, how the surface-active contaminants and thin water films interact is still not well understood. Researchers will investigate the processes that govern these complex interactions to improve the tools that scientists use to predict and to assess the contamination risks from human-made chemicals such as the perfluoroalkyl and polyfluoroalkyl substances commonly known as PFAS. The results of this research will lead to more effective cleanup strategies to reduce harm to human health from PFAS and similar contaminants. The scientists will use this research on groundwater PFAS contamination as a resource to collaborate with and support high school teachers with innovative curriculum tools, and training to engage Arizona high-school students, advance their interest in STEM, and enhance their experiential and critical thinking skills. The project goals are to advance the fundamental understanding of the thin-film-mediated retention and mass-transfer processes for surface-active contaminants in vadose zones and to develop a cross-scale framework that incorporates this new information to improve macroscopic transport models. The research will combine thin-film theory, experimental image characterization, and multiscale modeling approaches. The methodological approaches to differentiate the thin-film and bulk capillary air–water interfaces in soils will potentially transform how hydrologists conceptualize the movement of surface-active contaminants in vadose zones. The PI will partner with the University of Arizona’s cooperative-extension Arizona Project WET for Water Education, a STEM teacher in a Tucson public school, and a College of Education professor. Together, the project education team will develop, test, and formalize a fully inquiry-based educational program that involves hands-on experiences in building and using physical and digital models for deepening understanding and problem solving. The formalized educational program will be available to all high schools in Arizona via the existing infrastructure of Arizona Project WET supported by Tucson Water and the Arizona Department of Water Resources.This award is co-funded by the Hydrologic Sciences and Environmental Engineering programsThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.